I have a tool to drive drywall screws. Technically I have used it but only to make sure it works. The only drywall job I've got to in the house needed to be done faster than I could do it, so I paid someone else to do it.
I think I've got a heat gun based paint stripper that has yet to be used.
I don't suppose the question is intended to include things like the wire nuts that came in a box of 250, where some of them sit unused in a spares container, or the spare sanding belts I bought for the belt sander but just didn't get to use yet.